[Fatty acid composition of human breast milk across lactational stages in six representative cities in China from 2018 to 2019]

Objective: To investigate the fatty acid composition in breast milk at different lactation stages in six representative cities of China.

Methods: From January 2018 to December 2019, milk sampling of 690 healthy lactating mothers(full-term) in 5 lactation periods of 0-5 days, 10-14 days, 40-45 days, 200-240 days and 300-400 days was collected from 6 representative regions in China, with 23 cases of breast milk received in each lactation stage in each city. Mix it into one mixture, and make a total of 30 mixes. Determination of fatty acids in breast milk was conducted by gas chromatography-flame ionization detector.

Results: The contents of total fatty acids(TFA), saturated fatty acids(SFA), monounsaturated fatty acids(MUFA) and polyunsaturated fatty acids(PUFA) in breast milk increased with the progress of lactation and reached a relatively stable level after reaching a peak at 40-45 days. However, the composition ratio of SFA, MUFA and PUFA in TFA remained relatively stable from 0 to 400 days. The ratio of arachidonic to docosahexaenoic(AA/DHA) in breast milk from 0 to 400 days in the six cities ranged from 1.14 to 1.55, and there was no obvious trend of change in the whole lactation stage. The ratio of linoleic acid to alpha-linolenic acid(LA/ALA) in Chinese breast milk ranged from 3.84 to 18.94, showing significant regional variation.

Conclusion: The content and composition of fatty acids in breast milk of six cities in China vary to a certain extent and show a dynamic change process with the passage of time of lactation.